Title: Build, monitor, and measure your live safety case in nLoop

Author(s): Carmen Cârlan

Publication Event: Proceedings of the Thirty First Safety-Critical Systems Symposium

Publication Date: 2023-02-07

Resource URL: https://scsc.uk/r1729.pdf

Abstract:

To help AV companies to deploy safe, trustworthy autonomy, Edge Case Research proposes a new product – nLoop, which supports a new working model for building autonomous systems where the entire organization speaks the language of safety and measures progress continuously. nLoop’s live safety cases, requirements tracing, hazard tracking, and test coordination help teams achieve the goal of building AVs that are safe enough to deploy. At its core, nLoop supports the specification and management of structured safety cases. The validity status of the claims within nLoop safety cases may be evaluated by the evaluation of defined Safety Performance Indicators (SPIs), which, according to UL 4600, are metrics for assessing the system's safety performance. SPIs in nLoop are continuously evaluated based on the data coming from safety evidence providers (e.g., databases, issue tracking systems, external verification and validation tools) connected to the safety case via dynamic links, where the dynamic links allow the safety case to be aware of newly generated evidence both during design- and run-time. The evaluation of the SPIs enables the evaluation of the claims within the safety case, and, implicitly, the evaluation of the entire safety case. Consequently, safety cases in nLoop are ‘live’, keeping track of the status of the current safety performance of the overall system, given the available safety-relevant evidence. The validity status of the claims in the safety case may be used as feedback for system developers. Given the invalidation of a safety claim, system developers and operators may update the system so that the desired system safety performance is (re)established. System updates usually imply the generation of new safety evidence, which, via safety evidence providers, is used again for evaluating SPIs, thus creating a feedback loop between the safety case and the activities executed by system developers and operators.